How can you learn to think critically?

In his article `Teaching critical thinking: some lessons from cognitive science` (2005) Tim van Gelder formulates six basic principles in relation to critical thinking. These principles are partly about critical thinking itself, partly about how critical thinking skills can be acquired and partly about the best method of teaching critical thinking. Van Gelder`s article can be summarized as follows:

1. Critical thinking is hard
People are not critical by nature. Like ballet, critical thinking is a highly contrived activity. Running is natural; nightclub dancing is so to a lesser extent; but ballet is something that you can only do well after investing time and money in painful, intensive training for years.
Underpinning an opinion, providing reasons to justify a statement are not innate basic reasoning skills. Critical thinking is something that is referred to as a higher-order skill by cognitive scientists. That means that critical thinking is a complex activity that is built up out of other skills that can be acquired more easily, like linguistic competence and text comprehension. As a consequence, attending a short course is not enough to turn somebody into a critical thinker; critical thinking is something that requires a sustained effort.

2. Practice makes perfect
Take tennis, for example, which is a higher-order skill. To play good tennis you must be able to run, hit a forehand and a backhand and watch your opponent. But mastery of these separate skills is not sufficient. You must be able to combine them into a fluent interplay of actions that result in scoring a point. By merely reading a book about critical thinking you do not develop your critical thinking skills. That only happens when you practice intensively in a way that is also called `deliberate practice`: practice that is specific, determined and concentrated.

3. Transfer-oriented practice is required
Critical thinking should be trained as a separate discipline within a course; in addition, students must learn how to apply the acquired knowledge, skills and attitude to the other fields of their study. The entire curriculum should challenge the student to do so.

4. Theoretical knowledge is indispensable
Knowledge of a coherent conceptual framework makes it possible to spot and define mistakes in reasoning, and it increases the student`s capacity of self-reflection and self-criticism; it will also make it easier for teachers to provide feedback.
Having command of the lingo is like having x-ray vision into thinking. For example, if you know what is meant by affirming the consequent, it will be easier for you to find examples of poor reasoning, because you will be able to pick out the kind of reasoning that fits that particular pattern more quickly.

5. People are prone to stick to their own convictions
People are naturally inclined to stick to something that is old and trusted. Therefore, it is essential in education for the teacher to be a role model by continually adopting a critical, open and inquiring attitude and stimulating the development of that same attitude within their students.

6. Making argument maps improves critical thinking skills
A core part of critical thinking is in dealing with arguments. Visualizing arguments, argument mapping, stimulates the development of critical thinking skills. Rationale offers a very helpful tool to do that.